Fuel injection system for an internal combustion engine



June 28, 1966 H, E, JAKOB 3,258,254

FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE Filed Dec. 30, 1963 INVENTOR. HERBERT E.JAKOB MQJMM Aiiorneys United States Patent 3,258,254 FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE Herbert E. Jakob, 305 Knobloch Ave.,

Jelfersonville, Ind. Filed Dec. 30, 1963, Ser. No. 334,211 3 Claims. (Cl. 261-36) This invention relates to a fuel injection system for an internal combustion engine.

In the usual fuel system for such an engine, the vacuum inside the carburetor controls the rate of fuel flow. An object of this invention is to provide a system of fuel in ection for an internal combustion engine which controls fuel fiow independently of air fiow control.

A further object of this invention is to provide such a system in which an accurate fuel-to-air ratio is maintained at all engine speeds.

A further object of this invention is to provide such a system in which the rate of flow of fuel is not suddenly increased if a throttle valve of the carburetor is opened rapidly but is increased under control of the engine speed. A further object of this invention is to provide a fuel in ection system of this type in which fuel is delivered by a pump which is controlled by the engine and delivers fuel at a rate proportional to the rate of engine operation and in which the fuel delivered by the fuel pump passes through a variable orifice control valve which opens as the pressure of the fuel delivered by the fuel pump increases and in which the pressure of delivery from the variable orifice is limited to a predetermined pressure, the rate of delivery from the variable orifice valve to the carburetor being controlled by a valve which opens and closes with the air control valve.

The above and other objects and features of the invention will be apparent to those skilled in the art to which this invention pertains from the following detailed description, and the drawing, in which the drawing is a schematic view of a fuel injection system for an internal combustion engine constructed in accordance with an embodiment of the invention.

In the following detailed description, and the drawing, like reference characters indicate like parts.

In the drawing, a fixed displacement pump is indicated at 10. The pump is a portion of a fuel injection system for an internal combustion engine constructed in accordance with an embodiment of this invention. The engine, proper, is not shown in detail. The fuel pump draws fuel 12 from a tank 13 through a line 14. The fuel pump 10 is connected to and driven by driving portions of the internal combustion engine at a rate which can be proportional to that at which the engine is driven and can be somewhat greater than that required to drive the engine at any given speed. The fuel is delivered by the fuel pump 10 to a line 15 which divides into branches 16 and 17. The branch 16 connects with the interior of a cylinder 18 on one side of a piston 19 therein. The branch 17 is provided with a section 21 of restricted diameter and communicates with the interior of the cylinder 18 on the other side of the piston 19. Thus, when fuel flows through the restricted section 21 under drive from the pump 10, a pressure differential is set up on opposite sides of the piston 18 to urge the piston 18 to the right as indicated in the drawing. The maximum pressure inside the cylinder at the right-hand side of the piston 19 is limited by a relief valve 23. The relief valve 23 includes a piston 24 mounted for moving to the right and left, as shown in the drawings, inside a cylinder 25. A compression spring 26 urges the relief valve piston 24 to the closed position shown in the drawing. Pressure inside the line 17 urges the valve piston 24 to the 3,258,254 Patented June 28, 1966 right to open a discharge or by-pass line, 27 through which fuel is returned to the line 15.

Fuel from the right-hand end of the cylinder 18 passes through a variable orifice 29. The piston 19 carries a frusto-conic valve operating rod 31 which acts to increase the elfective size of the opening at the variable orifice 29 when the piston 19 and the rod 31 move to the right and decrease same when the piston 19 and the rod 31 move to the left. A compression spring 32 urges the piston 19 and rod 31 toward a normal position at which there is only a small opening at the variable orifice 29. As the pressure inside the branch 16 increases, the piston 19 and the rod 31 move to the right to increase the effective size of the variable orifice 29.

Fuel from the variable orifice 29 passes through a line 33 to a variable fuel flow control valve 34. The variable fuel control valve 34 includes an elongated stem 36 which is linked to a crank arm 37 by a link 38. The crank arm 37 is mounted on a shaft 39 which also carries a butterfly valve 41. The butterfly valve 41 controls flow of air through a throat 42 of a carburetor (not shown in detail). A conic tip 43 on the stem 36 moves to the left and right inside an orifice 44, and as the stem 36 moves from the full line position to the dot-dash line position, the effective opening at the orifice 44 increases. The stem 36, the butterfly valve 41, and the linkage therebetween is moved between the full line and dot-dash line positions by appropriate throttle mechanism (not shown).

When the throttle mechanism is actuated rapidly to open the butterfly valve 41 and the orifice 44 suddenly, flow of fuel into the throat 42 is only as great as can pass through the variable orifice 29 under the pressure determined by the relief valve 23, and only as the pump 10 speeds up as the speed of the engine increases is the piston 19 driven further to the right to open the variable orifice 29 and permit delivery of fuel at an increased rate as required by increased engine speed. Thus, there is not a sudden introduction of fuel into the throat 42 before the engine speed is sufiiciently great to use the fuel.

The fuel injection system illustrated in the drawing and described above is subject to structural modification without departing from the spirit and scope of the appended claims.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A fuel injection system for an internal combustion engine which comprises pump means, the pump means being driven at a rate proportional to the speed of the engine, means for supplying fuel to said pump means, a line receiving fuel from said pump means, there being a restricted portion in said line, whereby a pressure differential is set up in said line when fuel is pumped therethrough by said pump means, a cylinder having a head end connected to said line between said pump and said connected to said line on the other side of the restricted portion, a piston in said cylinder, means for resiliently urging the piston toward the head end of the cylinder, a pressure relief valve connected to the discharge end of the cylinder and discharging fuel when the pressure therein exceeds a predetermined pressure, there being an orifice in the discharge end of the cylinder for discharging fuel therefrom, a piston rod attached to said piston and having a frusto-conic portion reciprocable in said orifice, the elfective size of said orifice increasing as the piston moves toward the discharge end of the cylinder, a fuel receiving line receiving fuel from the orifice, a carburetor throat receiving fuel from the fuel receiving line. delivery valve means in said fuel receiving line, air valve means in the throat, and means linking the delivery valve means and the air valve means for opening and closing together.

2. A fuel injection system for an internal combustion engine which comprises pump means, means for supplying fuel to said pump means, a line receiving fuel from said pump means, there being a restricted portion in said line, whereby a pressure differential is set up in said line when fuel is pumped therethrough by said pump means, a cylinder having a head end connected to said line between said pump and restricted portion and another end connected to said line on the other side of the restricted portion, a piston in said cylinder, means for resiliently urging the piston toward the head end of the cylinder, a pressure relief valve connected to the other end of the cylinder and relieving the pressure when the pressure therein exceeds a predetermined pressure, means for dis charging fuel from the line on the other side of the restricted portion, valve means in the said fuel discharging means and connected to the piston so that the effective size of said fuel discharging means increases as the piston moves toward the discharge end of the cylinder, a fuel receiving line receiving fuel from the fuel discharging means, a carburetor throat receiving fuel from the fuel receiving line, delivery valve means in said fuel receiving line, air valve means in the throat, and means linking the delivery valve means and the air valve means for opening and closing together.

3. A fuel injection system for an internal combustion engine which comprises pump means, the pump means being driven at a rate proportional to the speed of the engine, means for supplying fuel to said pump means, a

line receiving fuel from said pump means, there being a restricted portion in said line, whereby a pressure differential is set up in said line when said fuel is pumped therethrough by said pump means, a cylinder having a head end connected to said line between said pump and restricted portion and another end connected to said line on the other side of the restricted portion, a piston in said cylinder, means for resiliently urging the piston toward the head end of the cylinder, a pressure relief valve connected to the other end of the cylinder and relieving the pressure when the pressure therein exceeds a predetermined pressure, there being an orifice in the discharge end of the cylinder for discharging fuel therefrom, a piston rod attached to said piston and having a portion of varying cross-section reciprocable in said orifice, the effective size of said orifice increasing as the piston moves toward the other end of the cylinder, a fuel receiving line receiving fuel from the orifice, a carburetor throat receiving fuel from the fuel receiving line, delivery valve means in said fuel receiving line, air valve means in the throat, and means linking the delivery valve means and the air valve means for opening and closing together.

References Cited by the Examiner UNITED STATES PATENTS 2,440,566 4/ 1948 Armstrong 15836.4 3,098,885 7/1963 Ball 26136 HARRY B. THORNTON, Primary Examiner.

T. R. MILES, Assistant Examiner. 

1. A FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE WHICH COMPRISES PUMP MEANS, THE PUMP MEANS BEING DRIVEN AT A RATE PROPORTIONAL TO THE SPEED OF THE ENGINE, MEANS FOR SUPPLYING FUEL TO SAID PUMP MEANS, A LINE RECEIVING FUEL FROM SAID PUMP MEANS, THERE BEING A RESTRICTED PORTION IN SAID LINE, WHEREBY A PRESSURE DIFFERENTIAL IS SET UP IN SAID LINE WHEN FUEL IS PUMPED THERETHROUGH BY SAID PUMP MEANS, A CYLINDER HAVING A HEAD END CONNECTED TO SAID LINE BETWEEN SAID PUMP AND SAID RESTRICTED PORTION, THE CYLINDER HAVING A DISCHARGE END CONNECTED TO SAID LINE ON THE OTHER SIDE OF THE RESTRICTED PORTION, A PISTON IN SAID CYLINDER, MEANS FOR RESILIENTLY URGING THE PISTON TOWARD THE HEAD END OF THE CYLINDER, A PRESSURE RELIEF VALVE CONNECTED TO THE DISCHARGE END OF THE CYLINDER AND DISCHARGING FUEL WHEN THE PRESSURE THEREIN EXCEEDS A PREDETERMINED PRESSURE, THERE BEING AN ORIFICE IN THE DISCHARGE END OF THE CYLINDER FOR DISCHARGING FUEL THEREFROM, A PISTON ROD ATTACHED TO SAID PISTON AND HAVING A FRUSTO-CONIC PORTION RECIPROCABLE IN SAID ORIFICE, THE EFFECTIVE SIZE OF SAID ORIFICE INCREASING AS THE PISTON MOVES TOWARD THE DISCHARGE END OF THE CYLINDER, A FUEL RECEIVING LINE RECEIVING FUEL FROM THE ORIFICE, A CARBURETOR THROAT RECEIVING FUEL FROM THE FUEL RECEIVING LINE, DELIVERY VALVE MEANS IN SAID FUEL RECEIVING LINE, AIR VALVE MEANS IN THE THROAT, AND MEANS LINKING THE DELIVERY VALVE MEANS AND THE AIR VALVE MEANS FOR OPENING AND CLOSING TOGETHER. 